A study from the University of Arizona shows that as global temperatures rise, vegetation will heat up faster than the air. According to scientists, this could increase pressure on ecosystems and reduce the ability of plants to absorb carbon dioxide (CO2).

The study indicates that by the end of the 21st century, plant canopy temperatures could rise by approximately 0.11°C more than air temperatures, increasing the gap between the two by 16%. Researchers note that many climate models do not account for this effect as they focus on air temperature rather than the temperature of the plants themselves.

Lead author Julia Green, Assistant Professor in the university’s Department of Environmental Science, said: “Plant surface temperature has a first-order impact on plant photosynthesis, transpiration, respiration and other important processes.

“Many of the researchers studying the impact of temperature on plants are using air temperature in their modeling – but our study shows that if you’re using air temperature alone, you’re going to be underestimating the temperature effects on plants.”

Effects on ecosystems and carbon storage 

Leaves can heat up to temperatures higher than that of the surrounding air because they absorb direct solar radiation. Under hot and dry conditions plants limit transpiration to conserve water, which reduces their natural cooling and leads to even higher temperatures.

According to the study, the temperature difference between plants and the air will increase in approximately 81% of vegetated areas, with arid and tropical ecosystems being the most severely affected. 

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This could reduce photosynthesis, weaken the capacity of forests to store carbon and speed up climate change.

The study shows that understanding how plants respond to rising temperatures is important for predicting the effects of climate change. 

Scientists believe that using more accurate climate models will help protect ecosystems, improve climate planning and support efforts to reduce CO2 emissions in the future. 

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